Unistrut roof rack - 41x41 or 41x21? Thoughts, opinions, experience?

[Guy]

As per the title I am going to build a Unistrut roof rack, probably then also bolting a Rhino roof rack to it too.

For the main stays/runners/track that I am bolting to the van should I go for 41x41 or 41x21, does anyone have any experience of advantages/disadvantages. They are both made of 2mm steel and I imagine are the same strength. The upside to the 41x41 would be more airflow under the solar panels when parked up but the downside equally would be more airflow when driving which I imagine means more noise.

I'm interested to know opinions please ..............and before anyone suggests I spend £X thousand on a roof rack, that just is not happening with the existing budget and probably never will, even if the budget were available

Thanks

 

[Guy]

The 41x21 doesnt clear the roof so its 41x41 all the way for the side runners/track

 

[Tor]

but 21mm high unistrut is almost half the weight and unlike the 41mm is fairly view free from the ground, plus as you will use fixings for whatever you wish to fit it doesn't really matter that it won't clear the roof.